Introduction
People have been using natural products since
the dawn of human history. Only toward the
end of the 19th century, however, have we
started to know something about the chemistry
of some of these products. With our increasing
knowledge of chemistry and related sciences,
we have begun to duplicate some of the natural
chemicals and at the same time make mod-
ifications in these compounds, or sometimes
produce completely new ones. Consequently,
since the advent of the Synthetic Era several
decades ago, many natural drugs have been
replaced by synthetic ones; natural flavors and
fragrances have been duplicated or simulated
by manufactured chemicals. However, the
number of natural products/natural product-
derived drugs used in pharmaceutical products
is still sizable, amounting to ca. 25% of the
total number of medicines approved by the
FDA. This number has not changed appreci-
ably for the last two decades, especially with
reference to botanicals. At least 250 plants or
their extracts are currently used in commercial
food products broadly classified as flavoring
ingredients (FEMA). Over the past decade,
there has been an increasing interest in the use
of natural products, particularly in foods,
cosmetics, and complementary medicine,
especially after the passage of the Dietary
Supplement Health and Education Act
(DSHEA) in 1994. The implementation of
DSHEA in the United States opened the mar-
ket to a new class of natural-based products
that are collectively known as dietary supple-
ments (more below).
To define a natural product is not a straight-
forward task, for, strictly speaking, everything
is derived from nature. Nevertheless, by natu-
ral products it is generally meant that products
are not made by chemical synthesis. Theoreti-
cally, a natural chemical is the same as
its synthetic counterpart in every respect.
However, it must be pointed out that unless
this chemical is absolutely pure (which it
seldom is), it would contain different impuri-
ties, depending on its sources. The impurities
present in a naturally derived food, drug, or
cosmetic ingredient are bound to be different
from those of its synthetic counterpart, and if
there is more than one way to synthesize this
compound, then the impurities would be dif-
ferent from one synthetic process to another.
The relative toxicities or merits of these small
differences have not been determined. If an
impurity, whether it is a natural or synthetic
chemical, has unusually high latent biological
activity, a minute quantity of it present in a
chemical would produce physiological effects
besides those elicited by the pure chemical
itself. These effects may not be immediately
apparent. Most, if not all, of existing standards
for food, drug, and cosmetic ingredients do not
have provisions for pinpointing small amounts
of impurities, as it is impractical to set abso-
lute purity standards for these ingredients.
Consequently, in practice, most of these ma-
terials are permitted to have a range of errors
built into their purity assays. This range of
errors can be due either to the assay methods
themselves or to actual impurities present in
the chemical. In some cases, as analytical
methodology advances, this range has become
progressively narrower. However, before this
range becomes negligible, one should not
equate a naturally derived chemical with its
synthetic counterpart, and their sources should
be indicated, as is the case with certain flavor
chemicals.
There are several definitions of a natural prod-
uct. In the case of flavoring substances, some
definitions of a natural product (flavor) limit
the product to be one obtained from natural
sources by physical processes only. Other
definitions allow hydrolysis and fermentationxxvii